It has been previously proposed to provide data logging apparatus for the use of salesmen, persons who are taking inventory, meter readers, or the like. However, these units have suffered from severe disadvantages in that they have been too heavy, inflexible and subject to entry errors by the persons who utilize them. Two typical units which have been proposed and which appear in the patent literature appear in U.S. Pat. No. 3,932,730 to B. F. Ambrosio granted Jan. 13, 1976; and U.S. Pat. No. 3,942,157 granted to L. L. Azure on Mar. 2, 1976.